3,133 research outputs found
Assembly via disassembly: A case in machine perceptual development
First results in the effort of learning about representations of objects is presented. The questions attempted to be answered are: What is innate and what must be derived from the environment. The problem is casted in the framework of disassembly of an object into two parts
How do robots take two parts apart
This research is a natural progression of efforts which begun with the introduction of a new research paradigm in machine perception, called Active Perception. There it was stated that Active Perception is a problem of intelligent control strategies applied to data acquisition processes which will depend on the current state of the data interpretation, including recognition. The disassembly/assembly problem is treated as an Active Perception problem, and a method for autonomous disassembly based on this framework is presented
Exact active subspace Metropolis-Hastings, with applications to the Lorenz-96 system
We consider the application of active subspaces to inform a
Metropolis-Hastings algorithm, thereby aggressively reducing the computational
dimension of the sampling problem. We show that the original formulation, as
proposed by Constantine, Kent, and Bui-Thanh (SIAM J. Sci. Comput.,
38(5):A2779-A2805, 2016), possesses asymptotic bias. Using pseudo-marginal
arguments, we develop an asymptotically unbiased variant. Our algorithm is
applied to a synthetic multimodal target distribution as well as a Bayesian
formulation of a parameter inference problem for a Lorenz-96 system
Unified microscopic approach to the interplay of pinned-Wigner-solid and liquid behavior of lowest-Landau-level states in the neighborhood of nu=1/3
Motivated by recent experiments, and using the rotating-and-vibrating
electron-molecule (RVEM) theory [Yannouleas and Landman, Phys. Rev. B 66,
115315 (2002); Phys. Rev. A 81, 023609 (2010)], in conjunction with exact
diagonalization, we develop a unified microscopic approach for the interplay
between liquid fractional-quantum-Hall-effect (FQHE) states and Wigner-solid
states in the lowest Landau level (LLL) in the neighborhood of nu=1/3. Liquid
characteristics of the FQHE states are associated with the symmetry-conserving
rotations and vibrations of the electron molecule. Although the electron
densities of the symmetry-conserving LLL states do not exhibit crystalline
patterns, the intrinsic crystalline correlations are reflected in the
conditional probability distributions and the emergence of cusp yrast states in
the LLL spectra. It is shown that away from the exact fractional fillings, weak
pinning perturbations (due to weak disorder) may overcome the energy gaps
between adjacent global states and generate pinned broken symmetry ground
states as a superposition of symmetry-conserving LLL states with different
total angular momenta. The electron densities of such mixed states (without
good angular momentum quantum numbers) exhibit oscillating patterns that
correspond to molecular crystallites. These pinned Wigner crystallites
represent finite-size precursors of the bulk Wigner-solid state. It is further
shown that the emergence of these molecular crystallites is a consequence of
the presence of RVEM components in the symmetry-conserving LLL states. In
addition, it is shown that the RVEM approach accounts for the Wigner-solid
state in the neighborhood of nu=1, which was also found in the experiments. We
utilize results for sizes in a wide range from N=6 to N=29 electrons, and we
address the extrapolation to the thermodynamic limit.Comment: 19 pages, 17 figures, 4 tables. For related papers, see
http://www.prism.gatech.edu/~ph274cy
Rising Powers in International Development: Building an Agenda for Collaboration
The Institute of Development Studies (IDS) launched the IDS BRICS Initiative in 2011, which aimed to examine the multi-faceted role of the BRICS countries – Brazil, Russia, India, China, and South Africa – as actors in international development. The Initiative was designed to promote learning from the experiences of the BRICS and other rising powers, and to stimulate debate on the implications of these countries’ growing importance for international development policy and practice, an arena where the BRICS have to date received limited attention from academia and policy-makers.
An initial consultation process carried out amongst IDS’ wide network of think-tanks, universities and civil society partners in 2011/12 across the BRICS countries showed there was significant interest in engaging in further discussions around this agenda. At the same time, IDS was awarded funding by UKAID, the British Department for International Development (DFID), which meant it was able to increase the scope of the BRICS Initiative and launch a full research programme, titled Rising Powers in International Development (RPID).
IDS marked the launch of the programme with a workshop which brought together participants from potential partner institutions in the BRICS countries to discuss an agenda for future collaboration in research, teaching, and policy work, focusing on development theory, development policy, development practice, and development resource flows; through conceptual and methodological framework development and scoping at the country level, in specific sectors, and in “AidLand” more generally.
The workshop brought together a diverse group of actors, including researchers and practitioners working in international development in the BRICS and beyond; and provided an opportunity to share and gain new perspectives on the state of the debate of development across the BRICS.DFI
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